Scientists Spot Powerful Antibody to Neutralize HIV Strains

The antibody was produced by an HIV-positive patient, and successfully neutralized strains resistant to similar antibodies.

The scientists, led by Mark Connors, M.D., Chief of HIV-Specific Immunity Section in NIAID’s (National Institute of Allergy and Infectious Diseases) Laboratory of Immunoregulation and Vaccine Research Center, have identified an astonishing antibody called N6, which can be used to treat or prevent HIV infection.

According to AIDS.gov, 36.7 million people worldwide currently suffer from Human Immunodeficiency Virus (HIV). Left untreated, HIV can lead to Acquired ImmunoDeficiency Syndrome (AIDS).

Unlike other diseases, you cannot cure HIV. However, through Anti-Retroviral Therapy (ART) the lives of HIV-affected people can be prolonged, and lower the chance of virus transmission. To facilitate the global eradication of HIV/AIDS and to develop a safe, adorable and scalable cure, NIAID invests in basic and clinical research.

Scientists tracked N6 over time to understand its process of ability in strongly neutralizing almost all HIV strains. This information might help in designing efficient vaccines.

Recognizing such neutralizing antibodies has been difficult because HIV virus eludes the immune system by rapidly changing its surface proteins. However, in 2010, an antibody called VRC01 was discovered by scientists at NIAID’s Vaccine Research Center (VRC), which can temporarily stop up to 90 percent of HIV strains from infecting human cells.

In current clinical trials, to notice the safe prevention of HIV infections, VRC01 is evaluated through intravenous infusions. Recent research suggests that N6 may lead over VRC01 as researchers may govern N6 subcutaneously rather than intravenously. In addition, the advantages may include stronger and more durable prevention and treatment strategies.

In the human body, the CD4 cells (T cells) help the immune system to fight the infections. HIV attacks specifically these cells by reducing its number in the body, making the person infection-prone and thus a weaker immune system. When the count of CD4 cells falls below 200 cells per cubic millimeter of blood (200 cells/mm3), the person enters the final stage of the virus, which is AIDS. However, not everyone who has HIV advances to this stage. Similar to VRC01, N6 prevents the virus from attaching to CD4 cells by blocking infection through binding to a part of the HIV envelope called the CD4 binding site.

This unique mode of binding depends less on the variable area called V5 region, which change relatively little among HIV strains. Thereby, N6 tolerate changes in the HIV envelope. Thus, HIV develops resistance to other VRC01- class antibodies in the V5 region by including the attachment of sugars.

“The discovery and characterization of this antibody with exceptional breadth and potency against HIV provides an important new lead for the development of strategies to prevent and treat HIV infection,”said NIAID director Anthony S. Fauci.